A farmer ploughs a piece of farmland on his tractor in Nong'an County, northeast China's Jilin Province, April 24, 2013. The Spring ploughing season is in full swing in northeast China. (Xinhua/Lin Hong) 

Farmers plough on a piece of farmland in Nong'an County, northeast China's Jilin Province, April 24, 2013. The Spring ploughing season is in full swing in northeast China. (Xinhua/Lin Hong)

Farmers on tractor prepare a piece of corn field in Nong'an County, northeast China's Jilin Province, April 24, 2013. The Spring ploughing season is in full swing in northeast China. (Xinhua/Lin Hong)

Farmers apply fertilizer to a piece of farmland in Nong'an County, northeast China's Jilin Province, April 24, 2013. The Spring ploughing season is in full swing in northeast China. (Xinhua/Lin Hong)

 Farmers are seen ploughing in a cotton field in Xiaozhai Township of Jizhou City, north China's Hebei Province, April 24, 2013. The Spring ploughing season is in full swing in north China. (Xinhua/Wang Xiao)

A woman sprays herbicide in a cotton field in Xiaozhai Township of Jizhou City, north China's Hebei Province, April 24, 2013. The Spring ploughing season is in full swing in north China. (Xinhua/Wang Xiao)